The inflammatory process, which forms an important part of the non-specific immune system, is characterized by a complex set of chemical and cellular changes that are essential for host defense in the face of microbial agents and other potentially harmful environmental factors. However, in many cases, inflammation may be triggered inappropriately, and/or may persist to a degree which becomes harmful to the host. In such cases, there may be a need to inhibit or prevent the development of one or more aspects of the inflammatory process, in particular, in cases of non-infectious inflammatory diseases.
A very large number of different chemical mediators have been shown to be involved in the development and control of the inflammatory process. Recent studies by a number of different laboratories have implicated nitric oxide (NO) as an important modulator of a variety of acute and chronic inflammatory disorders, including various types of arthritis, gastro-intestinal diseases, inflammatory conditions of the central nervous system and certain forms of asthma. Consequently, it has been proposed that inhibition of NO production could provide a useful therapeutic mechanism for the treatment and/or management of these inflammatory disorders. Furthermore, inhibition of NO synthesis has also been shown to be useful in some conditions or states that are not primarily inflammatory in nature. Thus, for example, inhibition of NO synthesis has been found to reduce glucose uptake into limb tissue in individuals with Type 2 diabetes during exercise.
The in vivo production of NO is mediated by a family of nitric oxide synthase (NOS) enzymes, including inducible-nitric oxide synthase (I-NOS), which is activated by many different immunological stimuli including lipopolysaccharide (LPS), interferon gamma and interleukin 1 (IL-1).
Several other compounds, including a number of natural products, have also been shown to inhibit NO production. The latter group includes compounds such as lutein [Rafi M. M. et al. Mol Nutr Food Res. 2007 March; 51(3):333-40; Choi, J. S. Nutrition. 2006 June; 22(6):668-71] and lycopene [Rafi, M. M. et al. J Food Sci. 2007 January; 72(1):S069-74]. However, the efficacy and potency of many of the natural product NO inhibitors have proven to be not particularly high. A need therefore exists for improved NO production-inhibiting compositions of natural origin.
Another highly important inflammatory mediator is the tumor necrosis factor-alpha (TNF-alpha), which is a cytokine produced by a variety of cell types including macrophages, neutrophils and lymphocytes. TNF-alpha occupies a key position in the early stage of the inflammatory process and is responsible for stimulating the production of other factors such as nuclear factor-κB which in turn causes activation of a wide range of pro-inflammatory genes. Thus, in view of its key pro-inflammatory role, TNF-alpha is clearly an important potential therapeutic target for anti-inflammatory agents.
It is a purpose of the present invention to provide a composition that may be used to inhibit the production of one or more key inflammatory mediators, such as superoxide NO or TNF-alpha, as a means for treating or managing pathological states and processes in which said mediators are implicated.
It is another purpose of the invention to provide a composition that is able to inhibit the production of the aforesaid inflammatory mediators with greater efficacy and/or potency than the compounds and compositions reported in the prior art.